/*!
 * Crypto-JS v1.1.0
 * http://code.google.com/p/crypto-js/
 * Copyright (c) 2009, Jeff Mott. All rights reserved.
 * http://code.google.com/p/crypto-js/wiki/License
 */

const Crypto = {};

(function(){

var base64map = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";


// Crypto utilities
var util = Crypto.util = {

    // Bit-wise rotate left
    rotl: function (n, b) {
        return (n << b) | (n >>> (32 - b));
    },

    // Bit-wise rotate right
    rotr: function (n, b) {
        return (n << (32 - b)) | (n >>> b);
    },

    // Swap big-endian to little-endian and vice versa
    endian: function (n) {

        // If number given, swap endian
        if (n.constructor == Number) {
            return util.rotl(n,  8) & 0x00FF00FF |
                   util.rotl(n, 24) & 0xFF00FF00;
        }

        // Else, assume array and swap all items
        for (var i = 0; i < n.length; i++)
            n[i] = util.endian(n[i]);
        return n;

    },

    // Generate an array of any length of random bytes
    randomBytes: function (n) {
        for (var bytes = []; n > 0; n--)
            bytes.push(Math.floor(Math.random() * 256));
        return bytes;
    },

    // Convert a string to a byte array
    stringToBytes: function (str) {
        var bytes = [];
        for (var i = 0; i < str.length; i++)
            bytes.push(str.charCodeAt(i));
        return bytes;
    },

    // Convert a byte array to a string
    bytesToString: function (bytes) {
        var str = [];
        for (var i = 0; i < bytes.length; i++)
            str.push(String.fromCharCode(bytes[i]));
        return str.join("");
    },

    // Convert a string to big-endian 32-bit words
    stringToWords: function (str) {
        var words = [];
        for (var c = 0, b = 0; c < str.length; c++, b += 8)
            words[b >>> 5] |= str.charCodeAt(c) << (24 - b % 32);
        return words;
    },

    // Convert a byte array to big-endian 32-bits words
    bytesToWords: function (bytes) {
        var words = [];
        for (var i = 0, b = 0; i < bytes.length; i++, b += 8)
            words[b >>> 5] |= bytes[i] << (24 - b % 32);
        return words;
    },

    // Convert big-endian 32-bit words to a byte array
    wordsToBytes: function (words) {
        var bytes = [];
        for (var b = 0; b < words.length * 32; b += 8)
            bytes.push((words[b >>> 5] >>> (24 - b % 32)) & 0xFF);
        return bytes;
    },

    // Convert a byte array to a hex string
    bytesToHex: function (bytes) {
        var hex = [];
        for (var i = 0; i < bytes.length; i++) {
            hex.push((bytes[i] >>> 4).toString(16));
            hex.push((bytes[i] & 0xF).toString(16));
        }
        return hex.join("");
    },

    // Convert a hex string to a byte array
    hexToBytes: function (hex) {
        var bytes = [];
        for (var c = 0; c < hex.length; c += 2)
            bytes.push(parseInt(hex.substr(c, 2), 16));
        return bytes;
    },

    // Convert a byte array to a base-64 string
    bytesToBase64: function (bytes) {

        // Use browser-native function if it exists
        if (typeof btoa == "function") return btoa(util.bytesToString(bytes));

        var base64 = [],
            overflow;

        for (var i = 0; i < bytes.length; i++) {
            switch (i % 3) {
                case 0:
                    base64.push(base64map.charAt(bytes[i] >>> 2));
                    overflow = (bytes[i] & 0x3) << 4;
                    break;
                case 1:
                    base64.push(base64map.charAt(overflow | (bytes[i] >>> 4)));
                    overflow = (bytes[i] & 0xF) << 2;
                    break;
                case 2:
                    base64.push(base64map.charAt(overflow | (bytes[i] >>> 6)));
                    base64.push(base64map.charAt(bytes[i] & 0x3F));
                    overflow = -1;
            }
        }

        // Encode overflow bits, if there are any
        if (overflow != undefined && overflow != -1)
            base64.push(base64map.charAt(overflow));

        // Add padding
        while (base64.length % 4 != 0) base64.push("=");

        return base64.join("");

    },

    // Convert a base-64 string to a byte array
    base64ToBytes: function (base64) {

        // Use browser-native function if it exists
        if (typeof atob == "function") return util.stringToBytes(atob(base64));

        // Remove non-base-64 characters
        base64 = base64.replace(/[^A-Z0-9+\/]/ig, "");

        var bytes = [];

        for (var i = 0; i < base64.length; i++) {
            switch (i % 4) {
                case 1:
                    bytes.push((base64map.indexOf(base64.charAt(i - 1)) << 2) |
                               (base64map.indexOf(base64.charAt(i)) >>> 4));
                    break;
                case 2:
                    bytes.push(((base64map.indexOf(base64.charAt(i - 1)) & 0xF) << 4) |
                               (base64map.indexOf(base64.charAt(i)) >>> 2));
                    break;
                case 3:
                    bytes.push(((base64map.indexOf(base64.charAt(i - 1)) & 0x3) << 6) |
                               (base64map.indexOf(base64.charAt(i))));
                    break;
            }
        }

        return bytes;

    }

};

// Crypto mode namespace
Crypto.mode = {};

})();

module.exports = Crypto;